So more 'games that you no longer think are awesome' than 'games that you think are no longer awesome', eh?
Anyway, Medal of Honor: Allied Assault. Sadly I never got the chance to play it when it was released, but playing it years later (which, at this point, is years ago), it didn't take much to notice it had some fairly poor level design, which killed a lot of fun that could otherwise have been there. At least that's what I think the issue was, but either way, it wasn't really what I expected from the game. I suspect the level design would have been considered at least decent back then, but it sure didn't feel that way when I played the game.